NO. 2057. THE GRASSHOPPER MICE—HOLLISTER. 449 



Measurements. — Averages and extremes of 21 adults from New 

 Mexico and Arizona: Total length, 159 (150-167); tail vertebrae, 49 

 (42-55); hind foot, 22.2 (20.5-24.0); ear from notch in dry skin, 15.6 

 (13.7-16.9). Skull: Condylobasal length, 26.2 (24.9-27.5); zygo- 

 matic breadth, 14.8 (13.9-16.2); interorbital breadth, 4.8 (4.4-5.2); 

 breadth of braincase, 12.8 (12.2-13.2); length of nasals, 11.2 (10.3- 

 11.8); length of mandible, 15.3 (14.3-16.2); maxillary tooth row, 4.4 

 (4.3-4.6). For detailed measurements of specimens, see page 478. 



Type-specimen. — No. 11091, collection of Academy of Natural 

 Sciences, Philadelphia. Skui and skull of old adult female (teeth 

 much worn). Collected September 19, 1898, by C. M. Barber. 

 Original number, 73. Rhoads collection. No. 4091. 



RemarJcs.— This is a dark form of the melanopJmjs type which seems 

 never to attain the light buffy pelage of the more northern race. It is 

 likewise darker and richer colored than arcticeps. Direct intergrada- 

 tion wdth melanophrys , arcticeps, and albescens is shown by numerous 

 intermediate examples from the borders of the range. Specimens 

 from Las Vegas, New Mexico, are approaching arcticeps in character. 

 The lightest colored specimens I have referred to ruidosx are from the 

 Lower Sonoran parts of southern New :Mexico, at Monument No. 15, 

 Mexican Boundary Line, and Jarilla. These specimens show such a 

 strong approach in color toward albescens of northern Chihuahua that 

 their determination as ruidosx seems perhaps unwarranted; but 

 albescens, as known from three specimens only is so very local that 

 until more complete collections from the general region are made it 

 seems best to consider these specimens as intermediates, and probably 

 nearest to ruidosse. 



Specimens examined.— Toial number, 150, from the following locali- 

 ties: 



New Mexico: Ancho, 1; Bear Spring Mountains, 13; Burley, 4; 

 Cactus Flat, 3 ; Capitan Mountains, 2 ; Carrizozo, 7 ; Datil I\Iountains, 2 ; 

 Deer Creek, Grant County, 2; Deming, 8; Fairview, 2; Gallina Moun- 

 tains, 4; Hale's Ranch, Riiidoso, 4 (Phila. Acad. Sci., type and two 

 paratypes and one in Amer. Mus.); Hatchet Ranch, 1; Jarilla, 1; 

 Lake Valley, 2; Las Vegas, 7; Magdalena, 1; Mangos Valley, 1; 

 Manzano Mountains, east side, 11; Mesa Jumanes, 11; Mesilla, 1 

 (Phila. Acad. Sci.); Monument No. 15, Mexican Boundary Line, 5; 

 Rio Alamosa, 1; San Augustine Plains, 7; San Pedro, 4; Socorro, 1. 



Arizona: Camp Verde, 2; Dos Cabesos, 2; Fairbank, 4 (Amer. 

 Mus. and Field Mus.); Lochiel, 1; San Bernardino Ranch, 1; San 

 Pedro River, 23; Taylor, 5; Willcox, 1. 



Sonora: Santa Cruz River, 4. 



Chihuahua: Colonia Diaz, 1. 



34843°— Proc.N.M.vol.47— 14 — ^29 



